Radio frequency (RF) microwave waveguide networks are attractive for numerous applications, where high radiation efficiency is required. The fabrication of the RF microwave waveguide networks is a multi-step process. When such networks include multi-component assemblies, separate fabrication of individual components is usually employed. These components can then be joined using one of numerous techniques, such as brazing, soldering or welding. In particular, dip brazing is considered as the most technically easy and relatively cheap method for fabricating RF microwave waveguide networks. This method employs a submerging of the components to be joined into a molten bath of salt or flux, followed by quenching them slowly in hot water to dissolve the salt or flux. Specifically, the fixtured assembly is preheated in an air furnace to insure uniform temperature of dissimilar masses in the assembly, and then immersed in a bath of molten salt that contains flux (also known as filler metal). The molten flux serves a multi-purpose role: providing heat transfer, supporting the assembly, and fluxing the joints through a capillary action. The immersion time required for dip brazing may vary, but usually it is less than two minutes. The assembly is then removed from the bath, cooled, and cleaned to be ready for further processing.
FIG. 1 schematically illustrates an example of a typical RF microwave waveguide network 10 that can be fabricated by dip brazing. The RF microwave waveguide network 10 includes a complex array of waveguide components 11 coupled together at joint nodes 12 for effective transferring RF microwave signals. To absorb undesired RF microwave energy, ferrite termination parts, such as dummy loads 13, are used in the network 10.
FIG. 2 illustrates a portion of the RF microwave waveguide network shown in FIG. 1 in a magnified form for a clarification purpose. As shown, the dummy load 13 is attached to a surface in a wall 111 of the waveguide 11, and is adjacent to an aperture to 14 in the wall of the waveguide 11.